The present invention relates to printing of documents using phase change ink, and more particularly to an improved automatic document feed characteristic of media printed with phase change inks.
It is a major benefit to allow printed material to slide through various types of paper handling equipment, such as office copiers, collators, paper folders and any other paper handling device that moves print media across a relatively stationary surface. Some types of inks, such as phase change inks, have sufficient friction against metal or glass surfaces that they cause documents to become jammed in the mechanical document handling equipment. This causes damage to the documents, possible contamination of the equipment, and delay and frustration for a customer while the jam is being cleared. Inability to have automatic document feed is viewed as a major shortcoming of such phase change inks.
What is desired are media printed with phase change inks that have a lower coefficient of friction to improve automatic document feed of such printed material through various paper handling equipments.
Accordingly the present invention provides an improved automatic document feed characteristic of phase change inks on a printed document by applying very small particles to the surface of the ink on the printed document. The very small, or fine, particles may be applied to the surface of a transfix drum to which the phase change inks are subsequently applied so that, when the image is transferred from the transfix drum to the media, the fine particles coat the surface of the phase change inks on the media. The fine particles may be applied subsequent to the printing process, whether offset or direct, by passing the printed document with the phase change inks through a pair of finish rollers with the fine particles applied to one of the finish rollers so that the fine particles are embedded into the phase change inks. The fine particles also may be applied as a specially designed hard ink in an overprint process. This overprint process may be done by means of a transfix drum or by directly printing onto the print media after the phase change ink has been applied. In a transfer process the overprinting may be done simultaneously so that when the phase change ink is transferred to the media, the hard ink coats the phase change ink on the media.
The objects, advantages and other novel features of the present invention are apparent from the following detailed description when read in conjunction with the appended claims and attached drawing.